Natural chromatin is heterogeneous and self-associates in vitro
The 30-nm fiber is commonly formed by oligonucleosome arrays in vitro but rarely found inside cells. To determine how chromatin higher-order structure is controlled, we used electron cryotomography (cryo-ET) to study the undigested natural chromatin released from two single-celled organisms in which...
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Published in | Molecular biology of the cell Vol. 29; no. 13; pp. 1652 - 1663 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
The American Society for Cell Biology
01.07.2018
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Online Access | Get full text |
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Summary: | The 30-nm fiber is commonly formed by oligonucleosome arrays in vitro but rarely found inside cells. To determine how chromatin higher-order structure is controlled, we used electron cryotomography (cryo-ET) to study the undigested natural chromatin released from two single-celled organisms in which 30-nm fibers have not been observed in vivo: picoplankton and yeast. In the presence of divalent cations, most of the chromatin from both organisms is condensed into a large mass in vitro. Rare irregular 30-nm fibers, some of which include face-to-face nucleosome interactions, do form at the periphery of this mass. In the absence of divalent cations, picoplankton chromatin decondenses into open zigzags. By contrast, yeast chromatin mostly remains condensed, with very few open motifs. Yeast chromatin packing is largely unchanged in the absence of linker histone and mildly decondensed when histones are more acetylated. Natural chromatin is therefore generally nonpermissive of regular motifs, even at the level of oligonucleosomes. |
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Bibliography: | Author contributions: S.C. performed experiments, project design, and writing; Y.S. performed experiments; C.C. performed experiments and editing; J.S. performed training; L.G. performed experiments, project design, and writing. |
ISSN: | 1059-1524 1939-4586 |
DOI: | 10.1091/mbc.e17-07-0449 |